Carburetors are equipments that mix the proportional gasoline with air in a vacuum condition generated by an engine so as to supply mixed gas to the engine. The carburetor is called as a heart of the engine due to its significant function, which mainly includes a start-up device, an idling device, a medium load device, a full load device and an accelerator. The carburetor can automatically prepare the desired mixed gas accordingly to different working status of the engine and output the mixed gas, further, the carburetor may atomize the fuel oil to make sure the uniformity of the mixed gas.
Dual fuel engines are new type engines that are able to use liquid fuel such as gasoline and gaseous fuel such as liquefied petroleum gas (LPG) or natural gas, which have good prospects due to high efficiency and low pollutant emission.
As shown in FIG. 1, a current dual fuel carburetor includes a carburetor body 1′ and a float chamber housing 2′ covered on the carburetor body 1′, and a float chamber 3′ is formed within the float chamber housing 2′. A main jet pipe 4′ is provided on the carburetor body 1′ to cooperate with the float chamber 3′, a main metering jet 5′ is provided on the fuel inlet end of the main jet pipe 4′, and a needle valve device is formed between the main metering jet 5′ and the float chamber 3′ to control the connection and disconnection therebetween. The needle valve device includes a pushing needle 6′ and a needle valve base 8′ cooperated with the pushing needle, and the needle valve base 8′ includes a valve base hole 81′ cooperated with the pushing needle 6′ and an fuel inlet 82′ communicated with the float chamber 3′, and the valve base hole 81′ is communicated with the main metering jet 5′. The pushing needle 6′ is driven by an electromagnetic valve 7′ which is mounted on the float chamber housing 2′. Conventionally, the pushing needle 6′ is integrated with the electromagnetic valve 7′, thus the pushing needle 6′ must be controlled by the electromagnetic valve 7′ which requires to be energized continuously during the operation, as a result, the electromagnetic valve 7′ may be damaged due to the long-term and continuous energization for the coils to make the carburetor unreliable.